It is often difficult for travelers to navigate in unfamiliar cities, particularly at nighttime or in other periods of limited visibility. Locating smaller streets and roads is often time consuming since street and roadsigns are often unlighted and/or obscured or partially obscured by trees and other vegitation. Most travelers use printed maps, but more recently GPS systems are becoming more available as are INTERNET navigation systems to electronically guide travelers. However, such electronic systems use prerecorded maps on CD-ROM or other recording medium and often do not contain information on current road repairs, newer streets, detours, and other changes that have occured since the map information was originally recorded. Furthermore at nightime and at other times of poor visibility, it is difficult to correlate the map information with visible landmarks, such as street signs.